Core B: Clinical Project Summary Core B: Clinical recruits, assesses, and follows all participants in the Knight ADRC Cohort. It uses well- established informant-based clinical and psychometric instruments (including the Uniform Data Set) at entry and annually thereafter to obtain clinical, cognitive, behavioral, and neurological data to carefully characterize each participant as to the presence or absence of dementia and, when present, its severity and etiology. The Core has successfully functioned to serve the needs of cutting-edge research projects of the Knight ADRC and its affiliated grants since its inception in 1985 and will continue to do so in the next 5-year funding period. The Core's Specific Aims in the proposed funding period are: 1. Maintain an current active cohort of participants (current N=272), carefully characterized as to the presence or absence of symptomatic AD, to support longitudinal studies of the clinical, cognitive, and biomedical correlates of symptomatic AD in comparison with cognitively normal aging and to mark the transition of participants with preclinical AD to cognitive impairment. 2. Annually enroll and assess 40 new participants age 65y or older (50y or older for symptomatic individuals), to replenish attritional losses and expand the active cohort to ~350. 3. Collect data, images, and biospecimens (DNA, CSF, plasma, dermal fibroblasts, and iPSCs) from participants as appropriate. 4. Solicit brain autopsy from all participants. 5. Continue to engage individuals in the African American community in St. Louis to promote the inclusion of African Americans in research. 6. In conjunction with the Research Education Component, use Core resources to train early stage investigators in dementia assessment, the heterogeneity of ADRD, and clinicopathological correlations that explore the multifactorial nature of AD. 7. Continue to ensure the broad sharing of Knight ADRC tools, data, and biospecimens and continue contributions to multicenter ADRD programs. 8. Address appropriate NAPA milestones related to cognitive data, longitudinal molecular phenotyping, sex and racial differences, sleep, and vascular contributions to dementia.